#include <iostream>
using namespace std;
int mod(string num,int a);

int main() {

    int t;

    cin >> t;

    while(t--)
    {
        long long int n;
        cin >> n;
        string k;
        cin >> k;
        int t;
        t = mod(k,n);

        if(t==0)
        {
            cout << 0 << endl;
        }

        else if(t < n/2.0 )
        {
            cout << 2*t << endl;
        }

        else if(t == n/2.0)
        {
            cout << 2*t - 1<<endl;
        }
        else
        {
            cout << 2*(n-t)<<endl;
        }



    }

	return 0;
}

int mod(string num,int a)
{
    int res = 0;
    int i;

    for(i = 0;i<num.length();i++)
    {
        res = (res*10 + num[i] - '0')%a;

    }

    return res;
}